Carbureter for gas-engines.



No. 825,499. PATENTED JULY 10, 1906. T. L. & T. J. STURTEVANT.

GARBURETER FOR GAS ENGINES.

APPLICATION FILED JULY 6. 1905.

ITED STATES PATENT OFFICE.

THOMAS LEGGETT STURTEVANT, OF QUINCY, AND THOMAS JOSEPH STURTEVANT, OF WELLESLEY, MASSACHUSETTS, ASSIGNORS TO STURTEVANT MILL COMPANY, OF BOSTON, MASSACHUSETTS, A COR- PORATION OF MAINE.

Specification of Letters Patent.

Patented July 10, 1906.

Application filed July 6, 1905- Serial No. 268,823.

To all whom it may concern:

Be it known that we, THOMAS LEGGETT STURTEVANT, residing at Quincy, and TuoMAs JOSEPH STURTEVANT, residing at Wellesley, in the county of Norfolk and State of Massachusetts, citizens of the United States, have invented or discovered certain new and useful Improvements in Carburetors for Gas- Engines, of which the following is a specification, reference being had therein to the accom anying drawings.

In t e use of explosion or gas engines more or less difliculty has been encountered by reason of the fact that it has been found to be difficult if not impossible to maintain at all 4 times the proper proportion of air and hydrocarbon spray for the gaseous-fuel mixture at different s eeds of the engine, and particularly so w on engines are running at very slow speeds and when the consequent suction for drawing in the liquid fuel is comparatively slight.

This invention has for its object to avoid the difficulty referred to by roviding in a carbureter automatic means w ereby when a relatively small volume of air is drawn into the carbureter and the engine is running slowly the passage-way for the air ast the spray-nozzle or the inlet for the liquid hydrocarbon fuel will be reduced in area, so that the velocity of the air past the said spray-nozzle or fuel-inlet will at all times be great enou h .to effect a proper spraying of the fuel. In other words, there is always a rapid current of air sucked ast the fuel-inlet, so as to spray theentering el properly.

The invention also com )rises an automatic governor orgoverning-va ve for the by-pass which permits the passage of gaseous fuel to the engine or motor when the throttle-valve is closed, so that when the engine or motor is running at a very slow speed by virtue of the fuel-supply admitted through the by-pass such slow s eed may be automatically regulated, and t us the engine at such times will .ble prevented from running too fast or too s ow.

In the accompanying drawings, Figure 1 is a partial vertical section of a carbureter embodying the invention, and Fig. 2 is an eleva- %ion of the same looking from the right of Referring to the drawings, 12 denotes a float-chamber liquid-fuel receptacle, which maybe of ordinary construction and to which the oil or other liquid fuel is fed from the main reservoir through the pipe 13, the fuel in said float-chamber being maintained at a constant level by a float-controlled valve in the usual manner. The main frame 14 of the carburetor, to which the fuel-receptacle is attached, is provided with an air-inlet at 15, communicating by a passage-way 16 with a mixing-chamber 17, which latter opens upward into the exit-passage 18 to the motor. The "float-chamber or fuel-receptacle communicates by a passage-way 19 with a small chamber 20, in which is located a needlevalve 21, which regulates the inlet of the liquid fuel passing into the mixing-chamber 17 through the spray-nozzle or fuel-inlet 22.

Located in the mixing-chamber 17 is an automatic vacuum-regulating valve 23, pivoted at its upper end to the carbureter-frame and pressed against by a s ring 24, artliy housed in a screw-plug 25, w ich ma e a justed to vary the tension of the sai spring, as may be desired. The automatic vacuumregulating valve 23 is normally held b said spring in the closed position, (shown in full lines in Fig. 1 but said valve will be moved backward toward or to the position denoted by dotted lines against the stress of the said spring, according to the pressure and volume of the air which may be passing into the carburetor and which volume of air will be in proportion to the speed and consequent suction or partial vacuum induced by the motor or engine.

Located between the mixing-chamber 17 and the exit-passage 18 is a throttle-valve 26, carried by a ivot-stem 27, provided with a crank or han le 28, by which the said throttle-valve may be opened or closed to admit more or less fuel to the engine. A by-pass by which a small quantity of fuel may be admitted to the engine when the throttle-valve is closed, so that the engine may at such times run at a very slow speed, is of course desirable, and in the construction herein shown this bypass is made through the stem 27 of the throttle-valve and which stem is formed hollow or with an internal chamber provided with an entrance-port 29 and an exit-port 30. Mounted within the said hollow stem of the throttle-valve is a conical governing-valve 31,

which is normally held away from its conical seat by a light spring 32, located between the head or nut 33 on the valve rod or stem 34 and a screw-plug 35, through which the said valve rod or stem passes. The head or nut 33 is preferably adjustable on the said rod or stem for the purpose of varying the tension of said spring, and thus adapting the governor-valve to different speeds.

The operation of the invention is as follows: When the engine is running slowly, so that the volume of air drawn into the mixing-chamber by suction is comparatively small, the swin ing vacuum-regulating valve 23 will be held y the spring 24 or other suitable means so near to the spray-nozzle or fuel-inlet 22 as to make the passage-way between the end of said nozzle (or the wall in the part in which the passage-way is formed) and the said valve so narrow that the limited volume of air will pass the fuel-inlet with approximately the same velocity that a larger volume of air will pass with the valve moved forward or away from such inlet or nozzle by the inward pressure of the larger volume of air when the engine is running rapidly, and thus the spray of the liquid hydrocarbon drawn inward or induced by the rapidlymoving small volume of air will be such as to maintain about the same proportion of hydrocarbon spray to the air at slow rates of speeds of the engine as at high rates of speed. In other words, the area of the air-passage at the spray-nozzle or fuel-inlet is automatically narrowed or reduced when the suction is light or feeble and is increased when the suc tion becomes greater, so that the velocityof the air flowing past the said nozzle will be relatively high at all s eed's of the engine, and the air-current will a ways he a rapid one at the said spray-nozzle or air-inlet. This is an important matter in that with carbureters as heretofore usually constructed it frequently occurred that the slowly-moving current of air passing the inlet-nozzle induced so little inspiration that the liquid hydrocarbon was not roperly sprayed, so as to produce a proper exp osive mixture for the efficient running of the explosion-engine. It will be observed that the fuel-inlet 22 is located a considerable distance above the lower end of the vertically-disposed automatic vacuum-regulating valve 23, the broad face of which is arranged opposite and approximately at a right angle to said fuel-inlet, so that any of the incoming oil or liquid fuel which fails to be instantly vaporized will be sprayed or discharged against the face of the said valve, and as it trickles down the same will be vaporized later by the inflowin-g air. If, however, there should be any surplus fuel which is not vaporized either instantly at its entrance or as it trickles down the. broad face of the regulating-valve, it Will be caught in the cup-like chamber or receptacle afforded by the U- shaped form of the carbureter-casing and will be taken up and vaporized later by the air-current. It will be seen that the U- shaped carbureter-casing or hollow frame is closed at its bottom and that the air-inlet passage-way 15 extendsdownward into the lower art 16 of the chamber of said frame and a so that the mixing-chamber -17 extends upward from said lower part. The cup-like receptacle afforded by the U-shaped carbureter-casing affords a safety-receptacle for any surplus or unvaporized oil or other liquid fuel, and thus not only prevents any waste of the same, but effectively avoids any drip from the carbureter, which is seriously ob ectionable in that the escaping fuel may possibly catch fire, and thus cause serious accidents. The byass which supplies fuel to the engine when t e throttle-valve is shut off is of such capacity as to permit of the passage of more than enough of the explosive mixture to run the motor or engine at the slow speed, and the governing-valve 31 in the said bypass will normally be so adjusted as to permit the passage of just about sufficient fuel or explosive mixture to run the en ine at the slow speed desired. If, however,t espeed of the engine or motor be accelerated, so as to exceed the slow speed desired, the suction due to the volume of explosive mixture flowing throu h the byass will act on the governing-va ve 3] an partly or wholly close the same by suction. against the stress of the light spring 32, thus checking the speed of the engine or motor until the suction falls below a certain point, when the valve will again be opened by its spring. Thus the bypass-governing valve 31 will act automatically-to maintain any desired slow speed of the engine or motor when the throttle-valve is closed and fuel is su plied to the engine or motor through the y-pass, and the rapid air-current past the fuel-inletcaused by the inward swing of the vacuum-regulating valve 23 to contract the air passageiway results in a proper fuel mixture at the slow speeds of the governed motor. Any desired slow speeds of the engine or motor when running with the fuel su plied through the by-passmay be provide for by varying the tension of the spring 32 by the adjusting-nut 33, as will be understood.

Having thus described our invention, we claim and desire to secure by Letters Patent 1. In a carbureter provided with a suitable spray-nozzle or fuel-inlet, the combination with a mixing-chamber and an air-inlet passage-way thereto, of an automatic vacuumregulating valve normally closing said air passage-way at or adjacent said nozzle or inlet and yieldingly mounted so as to open proportionally to the volume of air drawn in by suction, said valve extending below said in.- let or nozzle so as to receive, for subsequent vaporization, any liquid fuel not instantly vaporized.

2. In a carbureter, the combination of a suitable spray or fuel-inlet and an air-inlet passage-way thereto, with a ieldingly-mounted regulating-valve. norma ly closing said 'air and an air-inlet passage-way thereto, of anv automatic vacuum-regulating valve normally closing said air passage-way and between which valve and said nozzle or fuel-inlet the entering air passes to the mixingchamber, said valve being yieldingly mounted, so that the area of the air passage-way adj acent said fuel-inlet will always be in proportion to the pressure or suction, to cause a rapid current of air to pass said spray-nozzle or fuel-inlet at low speeds as well as at high speeds of the enigne or motor, said valve extending below said irilet or nozzle so as to re? ceive, for subsequent vaporization, any liquid fuel not immediately vaporized.

4. In a carbureter, the combination with a suitable spray-nozzle or fuel-inlet, as 22, of a swingingautomatic vacuum-regulatingvalve, as 23, normally closing the air assage-way at or adjacent said fuel-inlet and between which and the said nozzle or inlet the air passes to the mixing-chamber, and which is yieldingly mounted so as to open porportionally to the volume of inflowing air, said valve extending below said inlet or nozzle and toward thepassage for the incoming air, so as to receive, for

subsequent vaporization, any li uid fuel notinstantly taken u or vaporize as it enters the said mixing-c amber.

, 5. In a carbureter, the combination with a I suitable spray-nozzle or fuel-inlet, as 22, of a yieldingly mounted, vacuum regulating valve, as 23,'normally closing the air passageway at or adjacent said inlet and between which valve and the said nozzle or inlet the air passes to the mixing-chamben-aspring for moving said valve toward said closed'posltion against the pressure of the infiowing air, and means for regulating or varying the stress of said spring, said valve extending below said inlet or nozzle and toward the passage for the incoming air, so as to receive,

-for subsequent vaporization, any liquid fuel not instantly taken up or vaporized as it enters the said mixing-chamber.

6. In a carburetor ,the combination with a suitable spray-nozzle or fuel-inlet, of a verti cally-disposed air-regulating valve located opposite or approximately at a right angle to said nozzle or inlet so as to receive, in liquid form, any fuel discharged against the same and not instantly vaporized.

.7 In a carbureter, the combination with a suitable spray-nozzle or fuel-inlet, of a Vertically-disposed and yieldingly-mounted airregulating valve located opposite or approximately at a right angle to said nozzle or inlet so as' to receive, in liquid form, any fuel discharged against the sa'me and not instantly vaporized.

8. In a carbureter, a casing or hollowU- shaped frame closed at its bottom to afford a cup-like receptacle and provided with a spraynozzle or fuel-inlet discharging into the chamber of said casing or frame, combined with a verticall -disposed and yieldinglymounted air regu ating valve normally closing the air assage-way at or adjacent to said spray-nozz e or'fuel-inlet and extending below said inlet so as to receive, in liquid form and for subse uent vaporization, any fuel not immediate y vaporized as it enters the mixing-chamber.

9. In a carbureter, a casing or hollow U- shaped frame closed at its bottom to afford a cup-like rece tacle and rovided withaspraynozzle or fiiel-inlet ischarging into the chamber of said casing or frame, said chamber comprising an air-inlet passage-way opening downward into its lower part and a mixing-chamber or fuel-exit passage-way opening upward from its said lower part, combined with a vertically-dis osed air-regulating valve in said mixing-c amber opposite said fuel-inlet and extending below t 1e latter, so that any liquid fuel not instantly vaporized at its entrance will be received, in liquid form, by said valve, and so that any fuel not vaporized by the incoming air on said valve wi 1 be received in said cup-like receptacle for subse uent vaporization.

10. n a carbureter, a casing or hollow U- shaped frame closed at its bottom to afford a cup-like receptacle and provided with a spraynozzle or fuel -inlet discharging into t e chamber of said casing or frame, combined with an automatic or yieldingly-mounted and vertically-disposed air-regulating valve in said chamber and ad'acent said spray-nozzle or fuel-inlet, and which receives, in liquid form, the fuel not instantly vaporized, and which cu -like receptacle receives and holds the liqui fuel not vaporized on said-valve.

in testimony whereof we affix our signatures in presence of two witnesses.

THOMAS IJEGGETT STURTEVANT.

' THOMAS JOSEPH STUR'IEVAN'I.

Witnesses:

W. H. ELLEs, L. H. STURTEVANT. 

